Comparison of a 2-Dimensional Wear Scar Measurement and a 3-Dimensional Profilometer Measurement of the Same Wear Scar in a Point Contact

In a tribological experiment, one relies on the ability to measure accurately the wear scar in the contact. Usually, in a point contact, the wear scar diameter (WSD) is measured, and measurements of this kind may be compared for several different oils, for example. This type of experiment might be carried out on a ball-on-disk tribometer with a point contact, where the disk measurement might be considered of secondary importance. In a recent study, it was advantageous to measure the wear scar width (WSW) of the disk wear scar, which led to the question of whether the relative rankings provided by the WSWs would correspond to the more tedious profilometry that is often carried out in various tribological investigations. In this study of modern passenger car oils, we make that comparison and show that there is a 1-to-1 correspondence between the WSW determinations by optical microscope (OM) and the profilometry studies. These studies were carried out using the versatile and modified MTMTM tribometer.